<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <title>IFE ECMAScript</title>
</head>

<body>
    <div id="wrapper">
        <div id="news-top" class="section">
            <h3>Some title</h3>
            <div class="content">
                <ul>
                    <li><span>HTML</span><a href="">Some Link1</a></li>
                    <li><span>JS</span><a class="active" href="">Some Link2</a></li>
                    <li><span>CSS</span><a href="">Some Link3</a></li>
                    <li><span>JS</span><a href="">Some Link4</a></li>
                </ul>
            </div>
            <img src="">
            <p class="">Some Text</p>
        </div>
        <div id="news-normal" class="section">
            <h3>Some title</h3>
            <div class="content">
                <ul>
                    <li><span>HTML</span><a href="">Some Link1</a></li>
                    <li><span>HTML</span><a href="" class="active">Some Link2</a></li>
                    <li><span>JS</span><a class="active" href="#">Some Link3</a></li>
                    <li><span>CSS</span><a href="">Some Link4</a></li>
                </ul>
            </div>
            <img src="">
            <p class="">Some Text</p>
        </div>
    </div>
    <script>
        function getAllListItem() {
            // 返回页面中所有li标签
            let lis = document.getElementsByTagName('li');
            for (let i = 0; i < lis.length; i++) {
                console.log(lis[i]);
            }
        }

        function findAllHtmlSpanInOneSection(sectionId) {
            // 返回某个section下所有span中内容为HTML的span标签
            let spans = document.getElementById(sectionId).getElementsByTagName('span');
            let result = [];
            for (let i = 0; i < spans.length; i++) {
                if (spans[i].innerHTML === 'HTML') {
                    console.log(spans[i]);
                }
            }
        }

        function findListItem(sectionId, spanCont) {
            // 返回某个section下，所有所包含span内容为spanCont的LI标签
            let lis = document.getElementById(sectionId).getElementsByTagName('li');
            for (let i = 0; i < lis.length; i++) {
                if (lis[i].getElementsByTagName('span')[0].innerHTML == spanCont) {
                    console.log(lis[i]);
                }
            }
        }

        function getActiveLinkContent(sectionId) {
            // 返回某个section下，class为active的链接中包含的文字内容
            let section = document.getElementById(sectionId);
            let actives = section.getElementsByClassName('active');
            for (let i = 0; i < actives.length; i++) {
                console.log(actives[i].innerHTML);
            }
        }

        getAllListItem();
        findAllHtmlSpanInOneSection('news-normal');
        findListItem('news-normal', 'CSS');
        getActiveLinkContent('news-normal');
    </script>
</body>

</html>